Americans discard 4 billion tons of trash a year. This great quantity of mixed solid waste materials is becoming an increasingly burdensome environmental problem. One solution proposed in copending application Ser. No. 429,733 now abandoned filed Jan. 2, 1974 for reducing the volume of this waste material fragments it and biodegrades or composts the biodegradable parts for a fragmented and inoffensive product mixed with less-fragmented, non-biodegraded materials. The resultant waste thus will be a mixture of this biodegraded product and plastics, metals, and other non-biodegradable materials normally rejected as trash by households and industries. The proposed volume-reducing solution generally, therefore, is not applicable to largely metallic scrap such as junked cars or appliances.
There is interest in removing scrap that has value from discarded solid waste. The invention described herein facilitates the separation of valuable scrap from suitable waste, such as that processed by the proposed volume-reducing solution described above, and increases the efficiency of separation while reducing its costs.